Help with 'overlaid' logo bump on a object

Hello, first of all, if this is a repeated post my appologies.
I need some help with this scene i’m creating. Basicly a cretead a kettlebell with all the materials i wanted, included some bump mapping trying to achive ‘realistic modeling’. But now, i want to include a logo with another bumpmap on the front, like it´s carved on the object. Since i’m not used to Cycles Materials, i’ve tried to do by myself and researching on tutorials something, but without success. The closest i get it was with a Image Texture node, a Math node conect on the displacement slot in the Material Output, but it’s seems that i don’t have much of control to the bumping, and since the floor i’m using it’s black with another texture, the logo get’s even weaker, can barely see it.
Any help is more then welcome since, once again,i’m new to cycles material, and it’s killing me to understand it.
Here follow the images of the object and the node composition i’m using it.